Piston, cartridge, dispenser

1. A piston for a support sleeve of a dispensing assembly comprising a film bag cartridge, the piston comprising:

an at least substantially cylindrical outer shape;

a piston body; and

first and second film bag retainers arranged at opposite sides of the piston body, the first and second film bag retainers formed from materials more flexible than a material of the piston body, or

the first and second film bag retainers comprising components designed to be more flexible than parts of the piston body.

2. The piston in accordance with claim 1 , wherein the piston is configured to be operated with the film bag cartridge and each of the first and second film bag retainers is configured to interact with the film bag cartridge.

3. The piston in accordance with claim 1 , wherein the piston body has a disc shaped part and first and second projections projecting from the piston body at opposite sides of the piston body in a direction of the first and second film bag retainers.

4. The piston in accordance with claim 3 , wherein the first and second projections are ring-shaped projections, or

the disc shaped part comprises ribs at an outer circumferential surface thereof.

5. The piston in accordance with claim 4 , wherein each of the first and second film bag retainers comprises a central projection projecting towards the piston body, and the central projection of the first and second film bag retainers cooperates with a central aperture of a respective one of the ring shaped projections.

6. The piston in accordance with claim 3 , wherein each of the first and second film bag retainers comprises a central projection projecting towards the piston body.

7. The piston in accordance with claim 6 , wherein the central projection of the first and second film bag retainers cooperates with a respective one of the first and second projections.

8. The piston in accordance with claim 1 , wherein each of the first and second film bag retainer is received via one of a press-fit, a friction fit or a snap fit connection at the piston body.

9. The piston in accordance with claim 1 , wherein each of the first and second film bag retainer has a central part surrounded by a ring recess and a collar facing the central part.

10. The piston in accordance with claim 9 , wherein the central part of the film bag retainer comprises a front face remote from the piston body, with the front face forming a flat plane or an at least substantially flat plane, or

the front face projects by 20% to 75% of a height of the first and second film bag retainers beyond a height of the collar, with the height of the first and second film bag retainers being measured between the front face and a base of the first and second film bag retainers remote from the front face, the base facing the piston body.

11. The piston in accordance with claim 9 , wherein a base of the recess is spaced apart from the piston body by a gap, the gap having a height in a range of 0.7 to 2 mm.

12. A dispensing assembly comprising:

the film bag cartridge;

the support sleeve configured to accommodate the film bag cartridge; and

the piston in accordance with claim 1 accommodated in the support sleeve of a respective one of said one or more sleeves.

13. The dispensing assembly in accordance with claim 12 , wherein the cartridge is filled with a material.

14. The dispensing assembly in accordance with claim 13 , wherein the material is a mastic material.

15. A dispenser comprising:

a push rod configured to move the piston in accordance with claim 1 to and fro along a dispensing axis of the push rod, the push rod configured to be coupled to the piston or fixedly connected to the piston.

16. A piston for a support sleeve of a dispensing assembly comprising a film bag cartridge, the piston comprising:

an at least substantially cylindrical outer shape;

a piston body; and

first and second film bag retainers arranged at opposite sides of the piston body, each of the first and second film bag retainer having a central part surrounded by a ring recess and a collar facing the central part, and at least the collar and the ring recess and a sidewall of the central part comprising three or more slots that extend from a radial outer side of the collar towards the central part of the first and second film bag retainer.

17. The piston in accordance with claim 9 , wherein a base of the recess is spaced apart from the piston body by a gap.

18. A piston for a support sleeve of a dispensing assembly comprising a film bag cartridge, the piston comprising:

an at least substantially cylindrical outer shape;

a piston body; and

first and second film bag retainers arranged at opposite sides of the piston body, each of the first and second film bag retainer having a central part surrounded by a ring recess and a collar facing the central part, and a surface of the collar facing the central part comprises one or more recess or one or more projection.